In Annelids like earthworm and nereis, majority of gaseous exchange takes place through-----------.

Step-by-step solution

In Annelids such as earthworms and Nereis, there are no specialized respiratory organs like lungs or gills for the majority of gaseous exchange. They respire through their moist body surface (skin). The skin is kept moist by the secretion of mucus and coelomic fluid, which facilitates the diffusion of oxygen into the blood and carbon dioxide out of it. This process is known as cutaneous respiration. Book lungs are found in arachnids, tracheal tubes in insects, and book gills in horseshoe crabs. Answer: moist skin